The fire was reported about 3:45 a.m. on the pier just east of the intersection of Jackson Street and Loring Avenue, about a half-mile east of the Carquinez Bridge, according to Contra Costa Fire Assistant Chief Harold Burnett. The building was already heavily burning when firefighters arrived, Burnett said.

Crews started fighting the fire from the shoreline, but access was limited due to damage to the pier, which burned in a fire about two years ago, Burnett said. Contra Costa Fire Boat 84 fought the blaze from the water, and the United States Coast Guard also assisted.

A man walks his dog along railroad tracks as firefighters from the Crockett Carquinez Fire Protection District finish up at the site of a pier fire in Crockett, Calif. on Tuesday, Jan. 15, 2013. (Kristopher Skinner/Staff)

Firefighters had to run hoses over the nearby railroad tracks until they could dig under the tracks and run hose along the ground, Burnett said. Union Pacific and Amtrak trains were briefly delayed, but were running again as of 6:45 a.m.

The fire was declared under control around 6 a.m., though crews remained on the scene to find and extinguish hot spots, Burnett said.

The fire is being treated as suspicious, since there was no electricity service to the pier, Burnett said. Investigators will work the scene, but the pier is so heavily damaged, it may be difficult to pinpoint the cause, according to Battalion Chief Dean Colombo.